Materials Included In Kit

Additional Materials Required

Prelab Preparation

Each of the five lab stations should be set up to have three sets of the materials listed on each Lab Station Instruction Sheet, three copies of the instruction sheet, and one or more measuring devices. Each set of equipment can be noted as “A,” “B” and “C” and the Lab Station Instruction Sheets should be labeled accordingly. This stations laboratory activity can be set up so that three groups can work at any one lab station at the same time. Pairs of students may be assigned the letters “A,” “B” and “C” and should use the appropriately labeled set of equipment at each lab station.

To prepare the viscosity tubes at Lab Station 5, place one metal sphere in each of the soda bottle preforms. To six of the tubes add corn syrup until the syrup is level with the top of the tube, to avoid the formation of air bubbles. Tightly seat the cap on each corn syrup tube. Repeat the procedure for the other six tubes using polyvinyl alcohol solution.

Safety Precautions

Ammonium chloride and magnesium chloride are slightly toxic by ingestion. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Remind students to wash their hands thoroughly with soap and water before leaving the laboratory. Please consult current Safety Data Sheets for additional safety, handling and disposal information.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. All solid wastes from this laboratory activity may be disposed of according to Flinn Suggested Disposal Method #26a, in the regular trash. All liquid wastes from this laboratory activity may be disposed of according to Flinn Suggested Disposal Method #26b down the drain.

Lab Hints

• Enough materials are provided in this kit for 30 students working in pairs or for 15 groups of students. The five stations in this learner-centered, stations laboratory activity can reasonably be completed in one 50-minute class period, as long as the students rotate every 7–10 minutes. The prelaboratory assignment should be completed before coming to lab, and the Post-Lab Questions can be completed the day after the lab.
• In a 50-minute period, allowing students seven to eight minutes at each station will provide additional time to revisit a station that was not completed in the allotted time. If this occurs at the first station, it will give students an opportunity to work on their time management skills as they complete the remaining stations knowing they will only have time to return to one station in the end.
• Laminate the Lab Station Instruction Sheets to avoid damage during laboratory investigations. As an alternative to lamination, additional copies could be used to replace damaged Lab Station Instruction Sheets.
• Laboratory Station Instructions Sheets can be copied on colored cardstock paper so that each station is easily identifiable.
• The viscosity tubes at Lab Station 5 could also be used in a hot water bath. The temperature of the bath should not exceed 45 °C.

Teacher Tips

• Basic measurement is a must for every science and math discipline and is essential in addressing the National Science Education Standards. This station-based learner-center laboratory approach may be used to teach the techniques and equipment vital to measuring length, mass, temperature, time and volume throughout the math and science curricula.
• Teach basic measurement in conjunction with the history curriculum to provide a historical overview of the International System of Units, the scientists and agencies involved and the history of the natural and historical phenomena associated with measurement.

Answers to Prelab Questions

1. Identify the base SI unit for each of the following.
   1. Length

      The SI unit for length is the meter (m).

   2. Mass

      The SI unit for mass is the kilogram (kg).

   3. Temperature

      The SI unit for temperature is the degree Celsius (°C) or kelvin (K).

   4. Time

      The SI unit for time is the second (s).

   5. Volume

      The SI unit for volume is the liter (L) or cubic centimeter (cm³).

2. What tools are used to measure each of the following?
   1. Length

      Length is measured using a meter stick, metric ruler or metric tape.

   2. Mass

      Mass is measured using a balance or spring scale.

   3. Temperature

      Temperature is measured using a thermometer.

   4. Time

      Time is measured using a clock or stopwatch.

   5. Volume

      Volume is measured using either a metric ruler, if the object has a regular shape or by the displacement of water in a graduated cylinder or using an overflow can, if the object has an irregular shape.

3. Explain the difference in measuring the volume of an object of irregular shape and an object of regular shape. Is there a difference in measuring the mass of these objects? Explain.

   To find the volume of a regular solid, measure the length, width and height, then multiply these three values to determine the volume. The volume of an object with an irregular shape may be determined using the displacement of water. The object in question may be submerged under a known volume of water. The difference in the initial volume and the final volume is determined and that difference is the volume of the irregular-shaped solid. A graduated cylinder or an overflow can may be used to determine the volume. Mass is invariably measured using a balance—mass measurement does not depend on the shape of an object.

4. Explain the difference between the terms endothermic and exothermic.

   An endothermic process absorbs heat so the surroundings (container) feel cold to the touch. An exothermic process releases heat; therefore, the surroundings (container) feel warm to the touch.

5. Which of the following units would be the most appropriate to measure the distance between Hat Head, Australia and Uncertain, Texas—meters, kilometers, millimeters or centimeters?

   Kilometers would be the most appropriate unit in which to measure the distance between Hat Head, Australia and Uncertain, Texas. To avoid large, cumbersome numbers, very large distances are measured in kilometers. Unless otherwise specified, the unit used to measure an object depends on the size of the object being measured.

6. Why is it more appropriate to measure a person’s age in years rather than seconds?

   It is more appropriate to measure a person’s age in years rather than seconds because the measurement in seconds would be very large and changes too frequently. A measurement of age in years provides a reasonable number and is a large enough unit with a value that does not change as rapidly as the second.

Sample Data

Station 1

Station 2 Station 3 Station 4 Station 5

Answers to Questions

1. Although the mass of the objects at Lab Station 1 were easily measured on a balance, how might the mass of extremely small objects be measured?

   The mass of an extremely small object can be determined as an average of a measurable quantity of objects. For instance, the average mass of a single atom is determined by taking the average of 6 x 10²³ atoms (Avogadro’s number), which gives the average mass of the isotopes of the atom, not necessarily the exact mass of any one atom. If, however, all the objects have exactly the same mass, the average would be the exact mass of one of the objects.

2. 1. Using the data obtained from Lab Station 2, convert the measurement of the lab table and lab stool taken in arms and fingers into millimeters. Note: One arm equals 218 mm and one finger equals 13 mm. 

      Table
      4.2 arms x 218 mm / arm = 915.6 mm
      71 fingers x 13 mm / finger = 923 mm
      
      Stool
      2.8 arms x 218 mm / arm = 610.4 mm
      46 fingers x 13 mm / finger = 598 mm

   2. The measurements should theoretically be the same as those taken in millimeters using a ruler or meter stick. Were they? Why or why not?

      The measurements should theoretically be the same, however, they were not. The measurement with the finger is more precise than those with the arm because the finger is a smaller unit of measure. An even smaller unit of measure would have been closer to the measurement taken in millimeters.

3. Could the volume of an object with a regular shape be determined by using water displacement? Explain.

   Yes, the volume of an object with a regular shape may be determined either by multiplying the length, width and height, or by displacement. It is only irregular objects that, by definition, do not have these regular dimensions and must, therefore, be measured using water displacement.

4. The dissolution of which substance at Lab Station 4 could be used to make a cold pack? Which one could be used to make a heat pack?

   Ammonium chloride is endothermic when dissolved in water and could, therefore, be used to make a cold pack. Magnesium chloride is exothermic when dissolved in water and could, therefore, be used to make a heat pack.

5. How does lowering the temperature affect the viscosity of the corn syrup and polyvinyl alcohol solution? What would be the effect of heating on the viscosity of these two liquids?

   Lowering the temperature of corn syrup increased the viscosity (resistance to flow) of the corn syrup significantly, making the metal sphere take longer to travel down the tube. Therefore, it is a reasonable assumption that raising the temperature of the corn syrup would decrease the viscosity and allow the metal sphere to travel faster down the tube. Lowering the temperature of the polyvinyl alcohol solution did not significantly change its viscosity. The ball dropped very quickly down the tube for both tests. Therefore, one would assume that increasing the temperature of the solution would not significantly affect its viscosity.

Teacher Handouts

13526_Teacher1.pdf

Introduction

All students must learn basic measurement techniques to be successful in science class. Become measurement-savvy students with this introduction to basic measurement. Five lessons are provided in a stations approach to teach the concepts of time, mass, volume, temperature and length measurement as well as the use of appropriate tools.

Concepts

• Length measurement
• Temperature measurement
• Volume measurement
• Mass measurement
• Time measurement
• SI prefixes

Background

A fundamental requirement of any civilized society is the ability to make measurements. Five basic measurements that are essential in many scientific investigations are length, mass, temperature, time and volume.

Length is the spatial separation or distance between two points in relationship. Since 1983 the length of the meter has been defined using laser-based technology, most commonly the red 633-nm line of an iodine-stabilized helium–neon laser. The current definition states that a meter is the distance that light travels in a vacuum in 1/299 792 458 of a second (299 792 458 m s^–1 is the fixed value for the speed of light).

In the science classroom, the meter stick, metric tape measure or metric ruler are common tools used to determine length measurements. Most metric rulers measure length in both millimeters and centimeters—the longest lines on the scale, which are numbered, are centimeters, and the shorter lines between them are millimeters. Although often used in the United States to measure length or distance, the units inches, feet, yards and miles are considered “customary” or English units and are not SI units.

Mass, the amount of matter in an object, is one of the most fundamental of all physical measurements. In customary or English units, mass is measured in slugs. The SI unit for mass is the kg (for historical reasons it is not the gram). The kilogram is the only base unit in the International System of Units (SI) that is currently defined in terms of a physical artifact. Since 1889, the kilogram is equal to the International Prototype of the Kilogram (K), which is kept at the International Bureau of Weights and Measures (BIPM) in Sèvres, France. The cylinder is an alloy of 90% platinum and 10% iridium.

The National Institute of Standards and Technology (NIST), a nonregulatory federal agency in the U.S. Commerce and Technology Department, is working on a way to tie the measurement of the kilogram to an invariable natural constant. The mass of the kilogram would be accessible to researchers worldwide just as all other measurement standards are currently defined.

Temperature affects all living organisms. In the United States, temperature is most often in degrees Fahrenheit (°F), named after Daniel Gabriel Fahrenheit (1686–1736). The Fahrenheit Scale is a customary or English unit. Absolute temperature (T), the measure of the kinetic energy of molecules. Absolute temperature is measured in kelvin (K), named after William Thomson, 1st Baron Kelvin (1824–1907). Kelvin is defined as 1/273.16 of the thermodynamic temperature at the triple point of water. Absolute zero, or 0 K, is the temperature at which all molecular kinetic energy equals zero.

For many applications in the science classroom, temperature (t) is measured in °C (degrees Celsius). Celsius is also an SI unit; however, it is a derived unit and not a base unit. In other words, it is derived from the base unit for temperature, kelvin. Therefore, t = T – T₀, where T₀ = 273.15 K (the freezing point of water). Each Celsius degree is equal in magnitude to one kelvin. Therefore, to convert from kelvin to degrees Celsius, 273.15 must be added to the kelvin temperature value. To convert from Celsius to kelvin subtract 273.15 from the Celsius temperature value.

Temperature measurements are conducted with thermometers. Thermometers quantitatively measure temperature by using materials that change in some way when they are heated or cooled. In spirit- or mercury-filled thermometers, the liquid expands with an increase in temperature and contracts with a decrease in temperature. The expansion and contraction of the liquid in the thin-walled glass tube changes the level of the liquid. The level of the liquid is then read against a scale of numbers to determine the temperature. The amount of expansion or contraction is the same for each degree of temperature change, therefore, the scale on the thermometer is linear. In other words, each temperature division is an equal distance apart.

In an endothermic process, heat is taken in from the environment. In an exothermic process, heat is released into the environment. The temperature of the surroundings (container) of an endothermic process would feel cold to the touch. The temperature of the surroundings of an exothermic process would feed hot.

It has been important for man to mark the passage of time, from calendars that divide the days into months and years to clocks that divide the days into hours, minutes and seconds. Clocks have evolved from those crude enough to only tell morning from afternoon by casting shadows to those that are regulated by atoms. According to the National Institute of Standards and Technology (NIST), clocks must have a regular, constant or repetitive process or action to mark off equal increments of time, and also a means of keeping track of the increments of time and displaying the results.

The SI unit for time is the second (s). Although not SI units themselves, minutes and hours, which are multiples of seconds, are often used with time measurements. Sixty seconds is equal to one minute and 3600 seconds is equal to one hour. The second is defined as exactly the duration of 9 192 631 770 periods (cycles per second or Hertz—Hz) of the radiation corresponding to the transition between two hyperfine levels of the ground state (zero magnetic field) of the cesium-133 (Cs) atom, at rest at 0 K. In other words, the second is based on the frequency of cesium at very specific conditions. The second is defined using this natural phenomenon as a result of the invention of the atomic clock, since every element emits electromagnetic radiation at its own characteristic frequency. These frequencies are inherently stable over time and space.

Volume (V), the amount of space an object occupies, is considered a derived quantity and is based on the cubic meter (m³). The liter (l or L) is a unit that is accepted for use with the International System of Units (SI) but is not used when a high degree of accuracy is desired, or to express the volume of solid objects. Instead, the cubic meter or a multiple or submultiple thereof should be used to express volume with a high degree of accuracy or of an object with a regular shape. Although the symbols for SI are lower case, unless derived from the name of a person, the symbol for the liter is internationally recognized as either “l” or “L.” The capital letter is used to avoid confusion with the number one. The capital letter “L” is the only approved symbol to be used in the United States to avoid this risk of confusion. One liter is equal to 1 dm³ or 10^–3 m³. In other words, 1 cm³ is equal to 1 mL.

There are two major classifications of volume measurements, those of solids and those of fluids. Solids can be categorized as either regular or irregular in shape and fluids can be either liquids or gases. Regular solids have well defined dimensions of length, width, height and diameters, and may; therefore, be measured using a standard metric ruler. The volume of a rectangular solid, for example, is determined by multiplying the length times the width times the height. Irregular solids do not have well defined dimensions, and the volume of an irregular solid must therefore be measured using other methods such as water displacement. According to the principle of water displacement, if an irregular solid was placed in a container of water, the volume of water displaced by the object is equal to the volume of the object itself. Liquid volumes are commonly measured in graduated cylinders. A pipet, buret or volumetric flask is used when greater precision is needed to measure the volume of a liquid.

Adding SI prefixes to an SI unit creates the following multiples and submultiples

Note: The kilogram is the only base unit to include a prefix. All other prefixes attach to the word gram in the usual manner. The gram is defined as a derived unit equal to 1/1000 of a kilogram. If an equation requires the base unit, the kilogram should be used. While SI prefixes may be used with °C, they are typically only applied to kelvin. Although SI prefixes can be used with the second, they are not used with other time-related unit symbols (minute—min, hour—h, or day—d). Submultiples of the liter are common, but multiples of the liter are not.

Experiment Overview

Learner-centered stations are used to teach the basic concept of measurement. Rotate through each of five stations every 7–10 minutes. Each station provides an activity that allows you to practice a measuring skill using the appropriate tools.

Prelab Questions

1. Identify the base SI unit for each of the following.
   1. Length
   2. Mass
   3. Temperature
   4. Time
   5. Volume
2. What tools are used to measure each of the following?
   1. Length
   2. Mass
   3. Temperature
   4. Time
   5. Volume
3. Describe the different methods that are used to measure the volume of an object of irregular shape versus an object of regular shape. Is there a difference in measuring the mass of these objects? Explain.
4. Explain the difference between the terms endothermic and exothermic.
5. Which of the following SI units would be the most appropriate to measure the distance between Hat Head, Australia and Uncertain, Texas—meters, kilometers, millimeters or centimeters?
6. Why is it more appropriate to measure a person’s age in years rather than seconds?

Safety Precautions

Ammonium chloride and magnesium chloride are slightly toxic by ingestion. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Wash hands thoroughly with soap and water before leaving the laboratory.

Procedure

Preparation

1. Become familiar with reading the measurement equipment supplied at each station.
2. Follow any special instructions given by the instructor for the proper use of the measurement equipment and any other laboratory equipment used at each station.

Experiment

1. Proceed to one of the lab stations (1–5) as directed by the instructor.
2. Follow the instructions printed on the Lab Station Instruction Sheet located at each lab station.
3. Record the appropriate answers on the Measurement Worksheet as instructed on the Lab Station Instruction Sheet located at each lab station.
4. Rotate to the next lab station in numerical order when the instructor signals. This should be approximately every 7–10 minutes. Note: Students at station 5 should rotate to station 1.
5. Consult your instructor for appropriate disposal procedures. 

Student Worksheet PDF

13526_Student1.pdf